Hi Syd! Is that 2V at the input of the CMOS chip? That's definitely too low. The threshold level for CMOS lies at 50% Vcc or in this case 2.5V. Driving the input with less than this will at best drive the CMOS into the linear region of operation. What I could imagine here is that the input of the 4049 (possibly the ESD protection) is toast and poses a too low resistance to the driver from the other board...
Uwe. SLA> The trigger pulse is generated on a different board, then is conditioned SLA> with a 4049 cmos chip. It seems weak, but there are so many other problems, SLA> I am having trouble figuring out what it is supposed to look like. The 4049 SLA> is powered by a separate 5 volt regulator, but the input to it is only a 2 SLA> volt pulse, which seems too weak. >> >> How is the trigger pulse generated and what does it look like right >> now? If the original MOSFET was shorted, it probably also shorted >> either drain or source to the gate. This might have killed the driver >> circuit either by overloading it (short to ground) or by bypassing the >> high voltage pulse directly into the driver.... >> >> >> SLA> the 840 with regard to the trigger pulse? Most of these type tools SLA> use an >> SLA> SCR; this is my first experience with a mosfet fired transmitter. >> >> >> Uwe. >> >> -- >> Author: Uwe Zimmermann >> INET: [EMAIL PROTECTED] >> >> Fat City Network Services -- 858-538-5051 http://www.fatcity.com >> San Diego, California -- Mailing list and web hosting services >> --------------------------------------------------------------------- >> To REMOVE yourself from this mailing list, send an E-Mail message >> to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in >> the message BODY, include a line containing: UNSUB CHIPDIR-L >> (or the name of mailing list you want to be removed from). You may >> also send the HELP command for other information (like subscribing). -- Author: Uwe Zimmermann INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
